Sterilisation, such as sterilisation of a water supply, is of great importance generally, and especially in health care institutions such as hospitals, for example, where the water is to be used by patients who may be vulnerable to infection by water borne species.
Therefore, it is necessary to provide means by which water supplies may be sterilised and made contaminant free. There are a number of methods by which a water supply for a health care institution may be sterilised, including the use of radiation in the ultra violet region of the spectrum and chemicals such as chlorine, or ozone.
The use of ultra violet radiation requires any microbe within the water supply to be treated to be in direct line of sight of the radiation source for a sufficiently long period of time to ensure that the radiation is able to break down the microbe's cell wall. As such, the period of exposure and the distance from the radiation source are important factors that determine the efficacy of the treatment.
The use of chlorination to treat water has effectively reduced the incidence of waterborne disease but has a number of side effects. For example, if any naturally occurring organic compounds are present, chlorine will react to form potentially carcinogenic compounds, such as trihalomethanes and haloacetic acids.
The use of ozone (O3) has a number of benefits. Ozone is an extremely reactive allotrope of oxygen and will react with most contaminants in water, including viruses and bacteria. The high reactivity of ozone means that the lifetime of ozone within water is relatively short, before it will break down to form oxygen and water. In addition, the products of ozone reactions are generally harmless. However, the production of ozone is energetically expensive, generally requiring large equipment and power supplies. Therefore, ozone is typically only used for large scale sterilisation of a water supply in health care institutions such as hospitals, for example, where the cost of the equipment is justified by the volume of water that will be treated.
As such, ozone generators on the market are generally large, bulky devices and are designed for large throughput applications where large quantities of ozone are required to be produced. For example, a typical ozone generator comprises a metallic block through which a serpentine channel runs along which high pressure gas is forced to flow.
The metallic block is constructed to withstand large pressures of gas being forced along the serpentine channel and the large temperatures generated within the said serpentine channel. In addition, large dedicated power supplies are required, both adding to the expense of the system and making them unsuitable for treatment of small scale water supplies.
Accordingly, it is an object of the invention to provide an ozone generator that is suitable for sterilisation (for example, water treatment) that may be made cost effectively, is able to produce ozone efficiently and is scalable for small or large scale operations.